Villages in northern France have been sweltering this week as temperatures broke through the 40°C in what is already clearly going to be the fourth hottest year in recorded history.

At least 18 people reportedly died in France in the last week, including two children left in a hot car, after  temperatures records were smashed.

The annual disaster season of extreme weather is underway and Europe is already suffering from another heatwave that has sent the mercury rising. In its latest climate report, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) warns that heatwaves are going to be a permanent fixture on the calendar from now on and the death toll in Europe is already climbing.

The Climate Crisis is accelerating. The IPCC says that the Paris Agreement goal of keeping temperature increases to less than 1.5°C-2°C above the pre-industrial benchmark has already been missed and temperature increases are on course to reach a catastrophic 2.7C-3.1C by 2050 when large parts of the world will become uninhabitable.

Europe is going to be hit hard, says the IPCC as it is warming faster than the rest of the plant. The most urbanised continent by some distance, some 547mn people — 74% of the European population — live in towns and cities, and the EU's metropolitan regions, home to 39% of the bloc's population, generate nearly half its GDP. The IPCC's Sixth Assessment Report, in its chapter on European cities, shows clearly how fast the process is going.

The IPCC plots projected heat stress risk across Europe for the 2040-2060 period under four scenarios, ranked by decile from the lowest-risk dark blue through to the highest-risk dark red in a heat map of the Continent. The baseline panel — reflecting the 1986-2005 reference period — already shows the familiar north-south gradient: Britain, Ireland, France, Germany and Scandinavia sit predominantly in the cooler blue deciles, while a band of amber and light red risk runs through the Balkans, Greece and parts of southeastern Europe.

What changes across the subsequent three panels is the speed and scale of the shift southward and eastward into deep red. Under SSP1-2.6 — the IPCC's low-emissions, high-cooperation pathway model — northern and western Europe largely retains or even improves on its current risk profile, but the Balkans and parts of southeastern Europe darken into the highest decile.

Under SSP4-4.5 — a middle pathway model marked by high inequality — risk darkens across virtually the entire southern half of the continent, with the Iberian Peninsula, southern France, Italy and the Balkans all turning deep red.

By SSP3-8.5 — the high-emissions, low-cooperation model that has historically been used as a worst-case benchmark — the red zone has expanded further still, swallowing almost the entirety of southern and central-eastern Europe in the two highest risk deciles, leaving only Scandinavia, the British Isles and pockets of Western Europe in cooler categories.

The rising heat is going to kill more people each year. At 1.5°C of global warming, the IPCC projects approximately 30,000 annual deaths across Europe attributable to extreme heat — a figure that could nearly triple under 3°C of warming. The 2010 heatwave across eastern Europe, by comparison, killed an estimated 55,000 people in a single event, illustrating the scale of mortality a single extreme summer can already produce at current warming levels.

Southern Europe carries the heaviest burden in every scenario the report models. Heat-related mortality and morbidity are expected to be highest there, and to grow fastest, with the region's vulnerability compounding under the higher-inequality SSP3 and SSP4 pathways relative to the more cooperative SSP1. Heat-related respiratory hospital admissions across Europe are projected to rise from roughly 11,000 annually in the 1981-2010 reference period to 26,000 a year between 2021 and 2050 — a more than doubling driven chiefly by the rising frequency of extremely hot days in the south.

Cities compound the underlying climate signal rather than simply inheriting it. Three-quarters of Europeans live in urban areas, where the urban heat island effect, building density and air pollution interact to intensify the physiological impact of any given heatwave beyond what the raw temperature data alone would suggest.

The report's modelling finds that holding warming to the Paris Agreement's 1.5°C target rather than 2°C would, on its own, reduce summer premature deaths in large European cities by 15 to 22% — a single half-degree of difference translating into tens of thousands of lives across the continent's urban population over time.

The report does flag a genuine source of uncertainty that cuts against the starkest readings of the map: human acclimatisation. Evidence is emerging across most European regions of rising heat tolerance over time, and some projections that assume full physiological and behavioural adaptation suggest mortality rates could remain flat or even fall despite continued warming. The penetration of air conditioners will play an increasingly important role in European demographics as the crisis plays out; ubiquitous in America, air conditioner penetration in Europe is far lower, but that is starting to change as cooling becomes an existential question.

But the uncertainty around humanity's capacity to adapt to genuinely unprecedented heat extremes that fall outside the historical range entirely, remains large. The IPCC explicitly does not treat acclimatisation as a reason to discount the risk captured in the maps.